Sand blasting apparatus



Aug. 3%, 1931. LYTLE 1,819,331

SAND BLASTING APPARATUS Filed June 22, 1929 2 Sheets-Shes 1 Aug. 18, 1931. w. o. LYTLE 1,819,331

SAND BLAS'IING APPARATUS Filed June 22, 1929 2 Sheets-Sheet 2 INVENTOR Patented Aug. 18, 19 31 UNITED STA WILLIAM O. LYTL PATam omca p E, OF NEW KENS INGTON, PENNSYLVANIA, ASSIGNOR TO DUPLA'IE CORPORATION, A CORPORATION OF DELAWARE SAND BLASTING APPARATUS Application med J'ime 22,

The invention relates to sand blasting apparatus for markin hard substances such as glass. The particular apparatus shown is designed for, marking the trade-mark Duplate on sheets of composite glass, but designs of various kinds may be applied upon articles of a variety of shapes and of different materials upon which a sand blast will act effectively. Theprincipal objects of the inv'ention are to provide an improved "apparatus, which can be'operated with rapidityv and precision, which avoids scratching the glass, and which is economical in operation, both 4 as to sand and air. Certain embodiments of- 35 theinvention are illustrated in the accompanying drawings, wherein:

Figure 1 1s a vertical section on the line 'II of Fig. 2. Fig.2 is a plan View. (And Fig. 3 is a vertical section through a modification.

' Referring to the drawings, 1 is the framework of the apparatus" provided with a table made up of the members 2 and3, the members 3 being in the form of separated slats.

w The parts 2 and 3 are preferably of wood covered with sheets of felt 4, 5 to providea cushion for the glass sheets for which the apparatus isused. Supported beneath the top member 2 is a hopper 5 carrymg the sand w 6 which is employed in the marking operation. Anozzle 7 is also located in the hopper, such nozzle being provided with an air supply pipe 8 and a sand supply pipe 9, the

' connections to the nozzle being as indicated 5 in Fig. 1.

An opening through the table top is provided opposite theinozzle and in this opening is seated the conical shield 9 supporting a stencil plate 10, preferably of soft steel. This plate is cut through so as to form the word Duplate. This plate is removably" held in osition by screws 11, to permit its ready- ;rep acement as it becomes worn by the sand blasting operation. In the space surrounding the shield 9 is mounted a metal plate 12 ided for vertical movement by means of the bolts 13 and yieldingly held in upper position by means of springs 14 surrounding the 0 bolts. The upper face of this plate is covered with a layer of soft rubber 15. whose sur- 1929. Serial No. 872,983.

face"projects above the-surface of-the stencil plate and above the surface of the felt 4, as indicated in Fig. 1. When the composite plate 16 is slid into position over the stencil plate, it rides over the soft rubber layer 15 without contacting with such plate so that there is no danger of scratching the glass. When the sand blast is brought into play, the plate 16is pressed down so that its lower face closely approaches or engages the stencil plate 10. In this position the letter openings through the stencil plate are completely closed and the sand blast acts through such letter openings to give a clear cut reproduction of the stencil. i

The air is supplied to the pipe 8 from the pipe17 past a valve in the casing 18. This valve is provided with a stem 19 and the valve is yieldinglyheld in closed position by means of aspring 20. The stem 19 is engaged by a lever 21 pivoted at 22 and engaging the stop 23 when the valve is closed. The valve 1s opened from the foot treadle 24 pivoted at 25 and normally held in the position shown by means of the spring 26 which has its lower end connected to the lever by means of the -wire 27 and turn-buckle'28. The short end of the lever-24 has rock-ing engagement with the block 29 carried by the-lower end of the rod 30, such rod being slidably mounted'in' the sleeve 31. The nuts 32 carried by the rod 30 serve to limit its upward movement, while the downward movement islimited by means of the bolt 33. The rod 30 carries at itsupper end a latch 34 provided with the hook 35 at its lower end and engaged at its upper end by a spring 36 which normally presses the upper end of the latchto the left. When the parts are rin the position shown and the rod 30 moves upward, the hook 35 engages the end of the lever 21 and causes it to move up, thusopening the valve in the casing 18. On a further movement upward of the rod 30, the upper end of the latch 34 is engaged by the trip member 37-, and such upper end is cammed to the right, thus disengaging the hook 35 fromthe lever 21 and permitting the spring 19 to close the valve in the casing 18. It will thus be seen that the movement of the treadle 24 in one direction first opens.

the valve and then permits it to snap closed. The parts are adjusted so that this control movement of thetreadle gives just the right amount of opening to the valve to secure the desired sandblasting effect upon the glass.

' of the treadle, but there is no waste of sand and air due to a too prolonged opening of the'air valve. Increased speed of operation is also secured due to'this method of operation as only a single movement is uired in order to controlboth'movenients of t e air valve. Thearrangement shown with the hopper beneath the stencil plate alsopermits the sand to be used over and over again as there is practically no lgss.-.

i 3 illustrates a modification in which the s ape ofhopper- 38 is modified and the changed. The air is conducted to the nozzle 39 through the pipe 40 secured in position: in the block 41 by means 'of the screw 42. The sand supplynpipe 43 is arranged coni -centric with" the air supply pipe and termias the treadle 24 of F1 nates adjacent the lower end of the hopper.

When a plate to be marked is placed upon the table and the plat-e12 is pressed down, the head of-one of the bolts 13 makes a connection between a pairof adjacent conta'ct members 44 completing'anelectrical circuit through the wires 45, 46, these wires lyi in a power circuit including'the winding 0 a solenoid arranged so as to control an air valve in the connection 47. Therefore, when the plate 12 is pressed down, and the solenoid is actuated, air is admitted through the pipe 47 and the sand blasting action is con-. tinued as long as the glass plate is pressed down a ainst the stencil plate 10. When the glass p ate is lifted, the plate 12 moves up, breaking the connection between the conwhich maintains the air. valve open. This arrangement relieves" the operator of the necessity of operating a sefparate' device, such 1 or securin the application of the air,- order to avoi awaste of sand and air, the solenoid maybe arranged tooperate a device such-as thatshown in Fig. 1 and includingv the parts :21, 30,: 31, etc.

, blasting apparatus, it willbe understood that 1. Sand blasting apparatus comprising a table for supporting an article to be marked and-provided with an opening, a stencila late in such P y P p atiiig lever, and means intermediate the yalve and said lever wherebythe movement of the s the valve 1 opening at substantially the evel of .the table Yelb tfllly movable means having a face of soft material'also lying. in said opening and surrounding said plate with said face held yieldingly above. the surface'of the plate. anozzle beneath the plate in line therewith, and means whereby "abrasive under air pressure is supplied through the nozzle.

2..Sand blasting apparatus comprisin a table for supporting an article to be mar ed and provided with an opening, a stencil plate in such opening at substantially the level of the table, a vertically movable guard plate also lying in said opening surroundin the stencil plateand having a' surface 0 soft material, yielding means holding said guard plate with its surface above the level of the stencil-plate, a nozzle beneath the plate in line therewith, and means whereby abrasive under air pressure is supplied through the nozzle.

3. Sand blasting apparatus coniprisin a i table for supporting an article to bemar ed method of controlling the air 'valve is having a supporting surface of soft mate.- rial, and provided with an o ening, a stencil plate in suchopeninglat su stantially the level of the surface 'of t e table, a vertically movable guard plate also lying in said open; ing surrounding'the stencil plate and having a surface of soft material, yielding means holding said guard plate with its surface above'the level of the stencil plate, a nozzle beneath the plate in line therewith; and

is sup lied through thenozzle. f

4. and blasting apparatus comprising a table; having an opening carrying a stencil plate, a nozzle behindthe plate in line therewith having connection with an abrasive supply, and an air supply pipe, a valve in the air supply pipe, an operating lever, and,

means whereby abrasive under air pressure means intermediate the valve and said lever whereby the movement A 5. Sand blasting apparatus comprising a table having' an opening car 'ng a stencil plate, a' nozzle behlndthe late in line therewith having connection w1th a sand. supply and an air supply pipe, a valve in the air:

yieldirigly held close, anp'perlever in one direction first o and thenreleases 1t, permitting it to snap lshut. Whiletheapparatusis refenred to as a sand In testimony whereof, I have hereunto subscribedlmy' name this-5th day of June,

WILLIAM o.

of the lever in one direction opens an closes the a1ryalve; 

